1. Field of the Invention
This invention relates, generally, to automatic paper hole punches, for preparing paper for binding into a spiral notebook, for example. More specifically, this invention relates to a punch machine that has an improved die assembly and mounting means, allowing the die assembly to be quickly installed and removed without bolts, screws or housing panel removal.
2. Related Art
Many automatic punch machines have been built with die assemblies for punching holes through a stack of papers prior to binding. Typically, these die assemblies are bolted into the machine and can be removed for cleaning, replacement or adjustment only by partially disassembling the machine. Bolts, screws, housing panels, and sometimes other machine parts must be removed to remove and replace the die assembly. Although such punch machines can be built to operate effectively and reliably, maintenance of the die assembly is not quick or easy.
One automatic punch with a bolt-in die assembly is the "Versa-Punch.TM.", model VP-6000, made by Performance Design, Inc., of Boise, Id. This punch 100 is shown in FIG. 1A and 1B. This punch machine includes a die assembly with a plurality of punch pins that are forced generally perpendicularly through the paper near the paper edge. The paper is held vertically with its edge inserted into a slot in the die assembly. The punch pins are then driven across the slot to cut through the paper, creating a hole in each paper at the location of each punch pin.
In order to access the die assembly 102 of the Versa-Punch.TM. machine, the user must unscrew four screws or bolts 104 to remove a top cover 106 and a front cover 108. Then, to remove the die assembly, four bolts 110 must be removed to detach the die assembly from the machine frame and three more bolts 112 must be removed to detach the assembly 102 from the push-bar 114. To replace the die assembly, the procedure is repeated in reverse, with the user having to hold the die assembly in place to align it with the various bolt holes.
The die assembly 102 shown in FIG. 1B is a square-hole design, which includes a die and a pull-back bar that each have square holes and that are connected by stripper bolts and bushings. This die assembly 102 also includes push-pins and square-end punch pins. The push-pins are pushed into bores in the top of the pull-back bar to engage each punch pin, that is, to secure each punch pin in a position in the pull-back bar that will result in punching of the paper.
Another example of a prior art die assembly that may be used in the bolt-in system is illustrated in FIG. 2. This die assembly 102' typically includes a die 116 with paper slot and die holes, a pull-back bar 118 with holes for receiving a plurality of punch pins 120, and a backup bar 122 screwed onto the pull-back bar for keeping the pins in the pull-back bar. The pull-back bar 118 is connected to the die 116 by means of the stripper bolts. To punch paper, the push-bar 114 drives the pull-back bar 118 forward and backward on bushings on the stripper bolts 126, thus moving the punch pins 120 forward and backward in the die holes 128. The push-bar 114 is supported inside the punch machine 100 only by its attachment to the connecting rods and its being bolted to the die assembly 102.
These die assemblies 102, 102', and the many other typical assemblies made for various binding coils and combs, each has a uniquely sized, spaced and shaped set of holes which typically are centered along about a 14 inch length of the die that is typically centered between the two ends of the die. Therefore, when the user wishes to punch standard 8-1/2-.times.-11-inch paper instead of the 14-inch paper, the user must move the paper stop 60 to accommodate the paper and also move the stop each time he/she changes the die assembly. If this adjustment is not made, the punched holes are not centered along the 11-inch paper edge. The holes may be slightly offset to the right or left, and a partial hole may be cut at one or both ends of the paper edge. This results in inferior binding and an unprofessional appearance. For example, as shown with the prior art die assembly 130 of FIG. 7A, the paper stop and left edge of the paper are set at "S" for punching the 14-inch paper. When the same paper stop setting is used for 11-inch paper in this same die 130, the holes in the 11-inch paper are not centered and the far right hole 132 extends to or past the 11 inch paper edge. When maintaining the same paper stop position and switching to another prior art die assembly 134, again the holes are centered within the 14-inch length, but punching 11-inch long paper results in the holes not being centered along the 11-inch length and the far right hole 136 being nearly at the paper edge. To properly punch the 11-inch paper with these two dies 130, 134 requires adjustment of the paper stop to a different position than used for the 14 inch paper and to different positions for the two dies.